This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A268690 #7 Feb 11 2016 12:11:14 %S A268690 1,5,3,2,10,50,25,13,7,4,20,100,500,250,125,63,32,16,8,40,200,1000, %T A268690 5000,2500,1250,625,313,157,79,395,198,99,495,248,124,62,31,155,78,39, %U A268690 195,98,49,245,123,615,308,154,77 %N A268690 A268642 with a(n+1) = 5*n if ceiling(a(n)/2) is already in the sequence. %C A268690 It is conjectured that this is a permutation of the integers, along with any Seelmann sequence in which a(n+1) = M*n if the divide by 2 rule is not permitted, for any integer M>1 and not of the form M = 2^N. %Y A268690 Cf. A268642. %K A268690 nonn %O A268690 1,2 %A A268690 _David Seelmann_, Feb 11 2016